Neuroscientists and clinicians seek insight into the distribution and temporal orchestration of human brain regions involved in cognitive processes. Unfortunately, even the most advanced techniques available today for measuring human brain function offer compromises between spatial and temporal resolution. Methodological advances in non-invasive studies of the human brain will, thus, have a significant impact on the understanding of complex behavior, and help investigation of a variety of clinical abnormalities, such as those associated with stroke, brain tumors, Alzheimer's disease, and developmental disorders. The overall goal of the present project is to develop experimental and analytical methods for spatiotemporal imaging and modeling of the neural basis of perception, cognition and action. According to a general model, complex behavior results from the coordinated activity of spatially distributed neural systems, giving rise to brain-behavior relationships that re distributed in space and time. Advanced data acquisition and analysis methods have enabled non-invasive studies of these distributed brain systems at high spatial and temporal resolution. In this project, novel approaches will be developed that will focus on addressing neurophysiological hypotheses about the properties of cortical activity. Specifically, novel source estimation techniques for magneto- and electroencephalography (MEG, EEG) that will provide accurate localization in the presence of trial-to-trial variability in the amplitude, latency, and phase of oscillatory event-related responses (Aim 1). Connectivity information from high-resolution anatomical and functional magnetic resonance imaging (MRI) will be used to inform MEG and EEG analyses to identify patterns of activity in multiple networks of cortical areas during the performance of a visual attention task (Aim 2). Furthermore, methods will be developed and applied to characterize activations in terms of the hierarchical organization among cortical areas (Aim 3). Given the increasing availability of both MRI and EEG/MEG, our multimodal approach should have significant impact on advancing the understanding of the neural bases of complex behavior. The neuroimaging techniques developed may help the investigation of a variety of clinical abnormalities and developmental disorders.